a. Field of Invention
The present invention relates to trailerable structures with transporting features. More specifically, the present invention relates to an improved frame, which may be included within a structure, which frame or structure is capable of being a towable trailer system and has a retractable wheel and suspension system which is easily and safely locked and unlocked in the extended position by the positioning of a detachable towing member.
b. Discussion of Prior Art
Heretofore, most movable structures have required loading or mounting on separate wheeled carriers, such as trailers, for transportation. When such structures are large or heavy, loading and unloading them from a trailer frequently requires the use of hoists, lifts or ramps, all of which may present special safety risks and require expensive equipment. The frames of structures which are frequently loaded on to and removed from trailers usually have design or reinforcement features which allow them to withstand the stresses of being hoisted, loaded, and unloaded. Such design and reinforcement features may add to the cost of such structures. Also, it is often necessary to design and construct expensive custom trailers to transport structures which are large or have unusual shapes. After a structure is unloaded from a trailer, storage of the trailer may be a problem.
The disadvantages of using separate trailers to transport structures have led to some other attempted solutions. Many structures have been designed as trailers with wheels permanently affixed to them. When moved, such permanently wheeled structures are used with the trailer's wheels and other components in place. This may be detrimental to the intended use of the structure at its use site, as the exposed wheels, fenders, and towing member may have an adverse affect on its appearance. This may be especially detrimental when the structure is intended for use, for example, in making sales or for use at a social function. Furthermore, structures permanently mounted on wheels are usually raised significantly above the ground level, thus creating a safety hazard for people entering and leaving the structures. Additionally, because of their mobility, structures on wheels are easily subject to theft.
Another solution to this problem has been to build trailers with retractable wheels, for example as shown in Even, et al. U.S. Pat. No. 3,832,932. The system of this reference is designed for a rocket launching trailer which includes a chassis which is pivotally carried by a turret having feet adapted to be lowered to the ground surface, this lowering being associated with the raising of the wheels above the ground by jacks between the chassis and the wheels. The turret feet are separately adjustable to provide a stable base for the rocket launcher. While this design does provide stability to the structure when it is used, the appearance, the complexity, and the cost of manufacture are disadvantages to this prior art structure for most domestic applications to trailerable structures.
Another trailer system is taught in Patterson, U.S. Pat. No. 4,366,650. The design of the structure of this reference allows a drilling system to be moved between drilling sites. At the use site the wheels are lifted from the ground and stored in the structure, to allow part of the structure to be lowered to the ground while the remainder of the structure is suspended considerably above the ground. While this arrangement may work well for a drilling rig, it does not solve the portability problems of most domestic structures. For example, the working platform structure does not lower to ground level, the system is not attractive, and no provisions are indicated to insure the safety of the operation. Field U.S. Pat. No. 3,179,438 discloses a toggle actuated caster wheel system which would not work for structures to be trailered or for structures other than light weight carts.
Several references have been found which address trailer systems having removable components. These systems have several disadvantages. Removed components must be handled and stored and the maximum width of the structures themselves is often compromised by the extension of wheel assemblies.
Additionally, Century Industries Inc. of Sellerburg, Ind. is known to have advertised a trailerable structure which has wheel wells and wheels which are retractable into such wells at the use site. However, it is understood that an air suspension system is used to retract and extend the wheels which could fail catastrophically if an air leak should occur. Also, no failsafe system is known to exist which could preclude the retraction of the wheels while in the trailering mode.
It is therefore seen that none of the known prior art provides a simple and inexpensive trailer frame which may be included within a structure and which allows for a retractable wheel and suspension system which is safely locked in position by the simple placement of a towing member.